1. Field of the Invention
The invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display module including a light-blocking tape.
2. Discussion of the Related Art
According to the rapid development in information technology, flat panel display (FPD) devices, such as liquid crystal display (LCD) devices, plasma display panels (PDPs), electroluminescent display (ELD) devices and field emission display (FED) devices, have been developed and have replaced cathode ray tubes (CRTs).
Among these devices, liquid crystal display (LCD) devices are most widely used for monitors of notebook computers, monitors of personal computers and televisions due to excellent moving images and high contrast ratio.
Liquid crystal display (LCD) devices use the optical anisotropy and polarization properties of liquid crystal molecules of a liquid crystal layer to produce an image. The liquid crystal molecules have long and thin shapes, and because of the optical anisotropy property, the polarization of light varies with the alignment direction of the liquid crystal molecules. The alignment direction of the liquid crystal molecules can be controlled by varying the intensity of an electric field applied to the liquid crystal layer. Accordingly, an LCD device includes two substrates spaced apart and facing each other and a liquid crystal layer interposed between the two substrates. Each of the two substrates includes an electrode on a surface facing the other of the two substrates. A voltage is applied to each electrode to induce an electric field between the electrodes and the alignment of the liquid crystal molecules as well as the transmittance of light through the liquid crystal layer is controlled by varying the intensity of the electric field.
The LCD devices require an additional light source because the LCD devices are not self-luminescent. Therefore, a backlight unit is disposed at a rear side of a liquid crystal panel and emits light into the panel, whereby discernible images can be displayed.
FIG. 1 is an exploded perspective view of schematically illustrating a liquid crystal display (LCD) module according to the related art. FIG. 2 is a cross-sectional view of illustrating a part of an LCD module according to the related art.
In FIG. 1 and FIG. 2, a related art LCD module includes a liquid crystal panel 10, a backlight unit 20, a support main 30, a top cover 40 and a cover bottom 50.
The liquid crystal panel 10 substantially displays images. The liquid crystal panel 10 includes first and second substrates 12 and 14 facing each other with a liquid crystal layer interposed therebetween. A printed circuit board 17 is attached and connected at a side of the liquid crystal panel 10 via connecting means 15.
The backlight unit 20 is disposed under the liquid crystal panel 10. The backlight unit 20 includes a lamp 24, a reflection sheet 22, a light guide plate 26, and a plurality of optical sheets 28. The lamp 24 is arranged along an edge of at least one side of the support main 30. The reflection sheet 22, which may be white-colored or silver-colored, is disposed over the cover bottom 40. The light guide plate 26 is disposed over the reflection sheet 22, and the lamp 24 is disposed at a side surface of the light guide plate 26. The plurality of optical sheets 28 are disposed over the light guide panel 26.
Side surfaces of the liquid crystal panel 10 and the backlight unit 20 are surrounded by the support main 30 having a rectangular frame shape. The top cover 40 covers edges of a front surface of the liquid crystal panel 10, and the cover bottom 50 covers a rear surface of the backlight unit 20. The top cover 40 and the cover bottom 50 are combined with the support main 30 to thereby constitute one-united body.
Lights emitted from the lamp 24 are incident on the side surface of the light guide plate 26 and are refracted toward the liquid crystal panel 10. The lights are changed to have uniform brightness and high qualities through the plurality of optical sheets 28 and are provided to the liquid crystal panel 10. Accordingly, the liquid crystal panel 10 displays images.
Meanwhile, the support main 30 prevents the light guide plate 26 from shaking due to outer impacts or vibrations by. More particularly, the light guide plate 26 includes protrusions 26a, and the support main 30 includes fixing grooves 32 corresponding to the protrusions 26a. The light guide plate 26 is prevented from shaking by inserting the protrusions 26a of the light guide plate 26 into the fixing grooves 32 of the support main 30.
However, light leakage may occur due to the protrusions 26a of the light guide plate 26.
More particularly, lights incident on the light guide plate 26 are totally-reflected several times inside the light guide plate 26 and uniformly scattered. At this time, some of the lights are scattered toward the protrusions 26a of the light guide plated 26.
Even though the protrusions 26a are inserted into and surrounded by the fixing grooves 32 of the support main 30, the support main 30 is molded from a resin that transmit some lights. Therefore, some of the lights are transmitted through the support main 30 corresponding to the protrusions 26a of the light guide plate 26 and are leaked outside.
As shown in FIG. 3, the light leakage is visible to the naked eye and causes decreases of the brightness and color uniformity. Accordingly, qualities of an LCD device are lowered.